One of Latin America's most admired folk singers, Facundo Cabral, was killed in an ambush by gunmen in Guatemala on Saturday.

The interior minister, Carlos Menocal, said the Argentinian singer and novelist was on his way to Guatemala's main airport when three carloads of gunmen surrounded Cabral's vehicle and opened fire.

The minister said early investigations indicated the bullets were meant for the driver, Cabral's Nicaraguan concert promoter Henry Farinas, who was wounded.

Cabral, 74, rose to fame in the early 1970s, one of a generation of singers who mixed political protest with literary lyrics and created deep bonds with an audience struggling through an era of revolution and repression across Latin America.

The Guatemalan president, Álvaro Colom, said he had called his Argentinian counterpart, Cristina Fernández de Kirchner, to tell her of the killing. "It seemed to hit her hard and she asked me to keep her informed about how the investigation is developing," he told Argentina's Radio 10.

Colom later laid the blame at "people involved in organised crime. They are not street killers. It's a well-planned operation." Officials said they were not sure of the motive.

Cabral's vehicle was trailed by another carrying four bodyguards, who opened fire and tried to chase the attackers, Menocal said. Officials later found one of the vehicles apparently used in the attack alongside a road towards El Salvador. Menocal said flak jackets, pistols and the magazine of a Kalashnikov assault rifle were found inside. Menocal said Cabral had initially planned to take a hotel shuttle to the airport, but accepted a ride from Farinas.

Cabral became internationally known in 1970 through his song No soy de aqui ni alla – I'm not from here nor there – which was recorded hundreds of times in many languages. By the time Argentina fell under military rule in 1976, Cabral was identified as a protest singer, and he fled to Mexico where he kept recording, writing books and giving concerts.

His concerts were a mix of philosophy and folklore, spoken-word poems and music reflecting his roots in the gaucho culture of rural Argentina. On stage, he celebrated the wisdom of Mahatma Gandhi and Mother Teresa, the humanism of Walt Whitman and the observations of Argentinian writer Jorge Luis Borges.

"Facundo Cabral was our last troubadour. As much a philosopher-poet as a singer, he was a living testament to the search for what unites us in culture and society," said the Argentinian singer Isabel de Sebastian. "After his concerts, you'd feel that our life in common was richer, more mysterious, more profound."

He lived mostly on the road, in hotels and with friends, telling interviewers that he owned no home. He was particularly proud that Unesco declared him to be an "international messenger of peace" in 1996. By the end, he often used a cane and had trouble with his vision, but refused to slow down.

"I always ask God, 'Why have you given me so much?' You've given me misery, hunger, happiness, struggle, enlightenment ... I've seen everything. I know there's cancer, syphilis and springtime, and fried apple dumplings," Cabral said at 71, during an Associated Press interview in Miami.

He never thought of retiring. "I can't stop, I wouldn't be able to," he said. "I breathe on the road ... on stage I'm 50 years younger, it pleases me to excite people with life."